Variable metering pump

ABSTRACT

A variable metering pump comprising a plunger type pump unit; a reciprocating mechanism for reciprocating the plunger thereof consisting of a connecting rod and an Oldham coupling; a device for adjusting the stroke of the plunger; and a lubricating system for lubricating the sliding portions of the plunger, wherein adjustment by said device can vary the capacity of the pump during operation and the forward end of the reciprocating plunger always stops in the forward stroke at a fixed point in a pump chamber, no matter how the plunger stroke is changed.

United States Patent Sonobe 51* Oct. 17, 1972 [54] VARIABLE METERING PUMP 2,263,647 11/1941 Ryder ..74/44 72 Inventor: Kiyomi souobe, Saitama, Japan 2,929,334 3/1960 Panhard ..92/13 3,282,218 11/1966 Bauers ..74/600 [731 Asslgmfi Ltd-a Tokyo, Japan 3,388,637 6/1968 Haas et a1. ..92/13 22 Filed; July 197 3,486,455 12/1969 Jemison ..92/13 [21] Appl 159593 Primary Examiner-Martin P. Schwadron Assistant Examiner-A. l-lershkovitz [30] Foreign Application Priority Data Attorney-R. D. Flynn et a1.

July 16, 1970 Japan ..45/61985 Aug. 18, 1970 Japan ..45/81759 [57] ABSTRACT A variable metering pump comprising a plunger type [52] US. Cl. ..I'....92/l3.4, 417/415, 74/44, pump unit; a reciprocating mechanism for reci t- 600 ing the plunger thereof consisting of a connecting rod and an coupling; a device for adjusting the [58] Flam Search-m-74/441 5001 600; 92/13, stroke of the plunger; and a lubricating system for 92/1351; 417/569 lubricating the sliding portions of the plunger, wherein adjustment by said device can vary the capacity of the [56] References C'ted pump during operation and the forward end of the UNITED STATES PATENTS reciprocating plunger always stops in the forward stroke at a fixed point in a pump chamber, no matter 256,054 4/1882 Root 74/44 how the plunger Stroke is changed 1,821,502 9/1931 ElllS ..92/13 1,998,772 4/1935 Swartz et a1. ..92/13 8 Claims, 8 Drawing Figures 46 v 1 12:1 a :43 2 6323 6 65211? 22 r 1 y T'; 18 V l 59 2 -222 $321, 1 1 27 V I I; g 1 30 n------ 2 16 1 64 1 67 "1 111 & 2B 5 a, s as ,5 1f"\ 61! 35 16 y L a 32 5 q 53 52 3 51 54 11 f; a 11 1d z\v s 1 11 11 PATENTEDncI 17 m2 SHEU t (If 4 f mm VARIABLE METERING PUMP BACKGROUND OF THE INVENTION whose capacity can be varied during operation without decreasing its volumetric efficiency.

The prior art plunger type variable displacement pump had the drawbacks that adjustment of the plunger stroke unavoidably caused the shift of the forward endof the reciprocating plunger, leading to variations in the volume of a pump chamber and consequently the volumetric efficiency or performance of the pump and that where it was attempted to change the pump capacity when the plunger was operated with an extremely small stroke, then said change was inevitably accompanied with a decline in the volumetric efficiency.

SUMMARY OF THE INVENTION According to an aspect of this invention, there is provided a variable metering pump comprising a plunger type pump unit; a connecting rod rockably connected at one end to the plunger; an Oldham coupling consisting of a pair of guide blocks having grooves formed in the facing sides at right angles and provided with parallel but not coaxially arranged shafts and a crank ring fitted on both sides with guide rollers engaging said grooves and inserted into the other end of the connecting rod; means for shifting one of the guide members to adjust the stroke of the plunger; and a lubricating system for lubricating the sliding portions of the plunger and the crank ring.

An object of this invention is to provide a variable metering pump which is little subject to decreases in a volumetric efficiency with the resultant high linearity of performance characteristics and allows the preset capacity of a measuring device and the amounts actually measured to accord mutually with high precision.

Another object of the invention is to provide a variable metering pump permitting the variation of its capacity even during operation without resulting in a substantial reduction in a volumetric efficiency.

Another object of the invention is to provide a variable metering pump causing the plunger to make a reciprocating movement using a novel type of reciprocating mechanism.

Still another object of the invention is to provide a variable metering pump having a lubricating system for supplying lubricant from a centrifugal pump coupled with the drive shaft of said metering pump to the sliding portions and rotary members of the plunger.

A further object of the invention is to provide a variable metering pump which eliminates the necessity of using parts of precision work for which there are demanded particularly rigid tolerances, thus reducing manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view of a variable metering pump according to this invention;

FIG. 2 is a plan view, partly in section, of the pump of FIG. 1;

FIG. 3 is a perspective view of the dismembered parts of a crank mechanism;

FIGS. 4A to 4D illustrate the operation of the crank mechanism; and

FIG. 5 is a perspective view of a lubricating system taken out.

DETAILED DESCRIPTION OF THE INVENTION There will now be described by reference to the appended drawings a variable metering pump according to this invention. Throughout the figures, numeral 1 is a body of box construction containing the driving mechanism of the pump. On the side wall la of the body 1 is projectively formed a housing 2 in which there are received the later described plunger, piston and associated parts thereof. At the outer end of the housing 2 is disposed a pump unit 3. On the inner surfaces of two side walls 1b and (FIG. 2) perpendicular to the side wall 1a are mounted bearings 4 and 5. At the center of the box body is rotatably supported in a horizontal plane a shaft 6 having a driving worm 7.

On the side wall 1b of the body 1 is placed a hollow mount 8 on which there is fixed an electric motor or a power source 9. The driving shaft 9a of the electric motor projecting into the mount 8 is connected through a coupling 10 to one end. of the driving worm shaft 6.

Referring to FIG. 1, on an upper rib 1d and lower rib 1e horizontally disposed in the body 1 are mounted bearings 11 and 12, on which there is rotatably supported a connecting rod-driving shaft 13, which in turn is fitted with a driving worm wheel 14 engaging the driving worm 7. To the upper end of the connecting rod-driving shaft 13 is integrally fitted a lower (or first) guide block 15 having a flat upper surface 15a. In said upper surface 15a is formed at right angles to the connecting rod-driving shaft 13 a groove 16 whose central line perpendicularly intersects the axis of the connecting rod-driving shaft 13.

On the upper portion of the inner surfaces of the side wall 1a of the body 1 and opposite side wall 1f thereof are formed flanges l7 and 18. At the center of said flanges 17 and 18 is rotatably supported a shaft 19 having a feed screw 20 through bearings 21 and 22. To the feed screw 20 is screwed a guide member 23 so as to be moved along said screw 20 according to its rotation. To the lower end of the guide member 23 is fixed a downwardly extending cylindrical support member 24, into which there is fitted a revolving shaft 25 through bearings 26. At the lower end of the revolving shaft 25 is integrally formed an upper (or second) guide block 27 having a flat lower surface 27a, in which there is formed at right angles to the revolving shaft 25 a groove 28 whose central line perpendicularly intersects the axis of said revolving shaft 25.

Between the guide blocks 15 and 27 is placed a ring 29 having flat upper (or first) and lower (or second) surfaces on which there are mounted two pairs of rollers 30 and 31 in perpendicularly intersecting rows, which in turn are fitted into the grooves 28 and 16 of the guide blocks 27 and 15 respectively. An assembly of the guide blocks 15 and 27 and the ring 29 con stitutes an Oldham coupling.

Numeral 32 is a connecting rod, into one end of which there is inserted the ring 29, and the other end of which is rockably connected to a piston 33 sliding through a cylinder 34 received in the housing 2. The

axes of the connecting rod-driving shaft 13 and the revolving shaft 25 and that of the piston 33 are in the same plane. An assembly of the shafts 13 and 15, ring 29, connecting rod 32, piston 33 and cylinder 34 constitutes a reciprocating mechanism 35.

To that portion of the feed screw shaft 19 which faces the side wall If of the body 1 is fixed a worm wheel 36, with which there is engaged a vertically disposed worm 37. On that portion of the top side lg of the body I which faces the side wall If is mounted a reading device 38, to the lower end of whose casing 39 is fitted a bearing 41, which in turn supports one end of the worm shaft 40 of the worm 37, said worm shaft 40 penetrating the reading device 38. To the upper end of the worm shaft 40 is fixed a knurled knob 42. In the casing 39 of the reading device are received a pair of superposed gears 43 and 44. The lower first gear 43 is fixed to the worm shaft 40 and the upper second gear 44 having a number of teeth differentiated by one tooth from that of the gear 43 and is rotatably mounted on the worm shaft 40. To the lower end of the casing 39 is rotatably fitted an idle gear 45 engaging both of said paired gears 43 and 44. To the second gear 44 is fitted a dial plate 46 for indicating amounts of displacement between the connecting rod-driving shaft 13 and the revolving shaft 25 by sliding about the worm shaft 40. The top plate 47 of the reading device 38 has an opening 48 through which to observe reading indicated by numerical graduations on the dial plate 46.

To one end of the piston 33 is fixed through a fixing member 50 one end of a plunger 49. The plunger 49 is reciprocatably extended through a pumping housing 52 into a plunger chamber 51, and has the middle part supported by the inner wall of the pump housing 52 through a gland packing 53.

Numeral 54 is an inlet part communicating with the pump chamber 51 through a check valve 55, and numeral 56 is an outlet part communicating the pump chamber 51 through another check valve 57.

Throughout FIGS. 2 and 5, numeral 58 is a centrifugal pump rotatably supported by the worm shaft 6 for driving the reciprocating mechanism 35 so as to rotate with said shaft 6. The centrifugal pump 58 is connected through a piping 61 (FIG. to the inlet part 59 of an oil filter unit 60. The outlet part 62 of the oil filter unit 60 communicates through a piping 63 with the interior of the top end of the cylindrical support member 24. The bearings 26 in said support member 24 are connected through passages 64 to the groove 28 of the upper guide block 27 (FIG. 1). One end of a piping 66 is connected to another outlet part 65 of the oil filter unit 60 and the other end is fitted with a nozzle 67 facing the upper surface of the connecting rod 32. The oil filter unit 60 has a detachable filter element 60a fitted to the upper or side wall of the body 1. The base of the body 1 defines a lubricant reservoir 68.

There will now be described the operation of a variable metering pump according to this invention. When the driving worm 7 is rotated by the electric motor 9, the lower guide block is rotated through the driving worm wheel 14. Since, as previously described, the reciprocating mechanism 35 is of Oldham coupling type, upper guide block 27 is made to rotate through the ring 29 with the rotation of the lower guide block 15. When the connecting rod-driving shaft 13 and revolving shaft 25 are displaced from each other, then the ring 29 is guided into the grooves 28 and 16 formed in the upper and lower guide blocks 27 and 15 respectively through the two pairs of rollers 30 and 31 according to the rotation angle of the connecting rod-driving shaft 13, thereby causing the connecting rod 32 to slide lengthwise. Each of the pairs of said rollers 30 and 31 may consist of a single key.

FIGS. 4A to 4D present the relationship of the travelling distance of the connecting rod 32 and the rotation angle of the upper and lower blocks 27 and 15. O and 0 represent the central axes of the shafts 25 and 13 respectively. Referring to FIG. 4A, the groove 16 of the lower guide block 15 is at right angles to the axis of the cylinder 33, and the axis 0 is displaced for a distance 6 to the left of the axis 0 At this time, that end of the connecting rod 32 which faces the piston 33 takes a most advanced position (hereinafter referred to as the forward stroke). When the lower block 15 rotates, for example, through an angle 0 from its position shown in FIG. 4A, then the connecting rod 32 indicates a displacement y from the end point of the forward stroke.

FIG. 4C represents the case of 0 at which time the connecting rod 32 makes a maximum displacement e from said end point. FIG. 4D denotes the case where the lower block 15 rotates through an angle of 0), that is, where the connecting rod is displaced for a distance of y.

While the lower block 15 continues rotation, the connecting rod 32 reciprocates between the end point of the forward stroke and a point displaced for a distance e from said end point causing the piston 33 to reciprocate for the same distance as 6.

When the plunger 49 retracts itself, operating liquid is sucked into the pump chamber 51 from the inlet part 54 in amounts corresponding to said retraction. Conversely, when the plunger 49 advances, the liquid is pressurized and delivered in amounts corresponding to said advancement from the pump chamber 51 through the outlet port'56 to the outside. The check valves 55 and 57 play the role of preventing the backward flow of the liquid.

Displacement of the axial center of the revolving shaft 25 and worm driving shaft 13 is effected by rotating the knob 42 and in consequence the feed screw 20 through the adjusting shaft 40, worm 37 and worm wheel 36 and moving the guide member 23 along the feed screw 20. In this case, the extent of said axial center displacement can be arbitrarily defined while observing reading in the dial plate 46 through the opening 48. When the axial centers of the shafts 25 and 13 are aligned, then the amount of delivery will become zero.

Since the variable metering pump of this invention is constructed as described above, displacement e of the axial center of the upper and lower guide blocks 27 and 15 represents the stroke of the plunger 49, so that amounts of operating liquid delivered from the pump unit 3 bear an extremely exact proportion to the extent of said axial center displacement 6. Since this displacement 6 is adjusted by moving the upper guide block 27, and not the connecting rod 32, the end point of the forward stroke is always fixed regardless of the extent of said axial center displacement 5, thus enabling the deepest point reached by the plunger 49 when inserted into the pump chamber 51 and in consequence the resulting volume of said chamber 51 to be always fixed. Accordingly, the performance characteristics of the metering pump of this invention maintains a high linearity over a broad range of operation. The axial center displacement e is effected by rotating the knob 42 to move the guide member 23, so that said displacement 6 bears an exact proportion to the degree of rota- 1 tion of said knob 42. This enables not only the pump output accurately to agree with reading on the dial plate 46 indicated by numerical graduations impressed thereon at an equal space, but also said pump output to be automatically set at a prescribed value by rotating the feed screw 20 using an electric motor and positioner, thereby permitting remote control. As previously described, the metering pump of this invention eliminates the necessity of using parts of high precision work with the resultant decrease in manufacturing cost. Further, if the body 1 is constructed in two or three blocks, it will offer the advantage of facilitating the fitting and removal of the reciprocating mechanism.

There will now be described the operation of the lubricating system. During the operationof the variable metering pump, the centrifugal pump 58 is actuated by rotation of the worm shaft 6 to suck up lubricant from the lubricant reservoir 68. The lubricant is supplied through the piping 61 to the oil filter unit 60 to be filtered by the filter element 60a. Part of the filtered lubricant is conducted through the piping 63 to the bearings 26 and then through the passages 64 to the upper and lower blocks 27 and and the sliding portions of the ring 29, while the remainder of the lubricant passes through the piping 66 to be dripped on to the connecting rod 32 from the nozzle 67. During the pump operation, the sliding portions. of the ring 29 are forcefully supplied with lubricant, thereby reducing the possibility of said portions being subjected to excess heat buildup or wear and also preventing the lubricant itself from being deteriorated by high temperatures which would otherwise occur. Moreover, attachment of the centrifugal pump to the worm driving shaft eliminates the necessity of providing any extra driving device to drive said pump, so that it is possible to realize the miniaturization of the variable metering pump. Since the lubricant is filtered by the filter element before application, it is free from any foreign matter, thus increasing the durability of the aforesaid sliding portions of the ring 29.

What is claimed is:

1. A variable metering pump comprising:

a pump unit including a plunger;

21 first guide block rotated by a power source;

a second guide block facing the first guide block;

a first groove formed in that surface of the first guide block which faces the second guide block;

a second groove formed in that surface of the second guide block which faces the first guide block;

a ring disposed between the first and second guide blocks and having rollers mounted on first and second flat surfaces thereof in perpendicularly intersecting rows with one set of said rollers fitted into said first groove and the other set fitted into said second groove;

a reciprocating mechanism including a connecting rod, into one end of which there is fitted the ring and the other end of which is connected to the plunger of the pump unit;

means for causing the second guide block to slide over the second flat surface of the ring thereby to adjust the strokes of the plunger of the pump unit; and

a lubricating system for lubricating the sliding portions of the reciprocating mechanism.

2. The variable metering pump according to claim 1 wherein the plunger stroke adjusting means comprises:

a reading device including a first gear fixed to a shaft for driving the plunger stroke adjusting means, a second gear having a number of teeth differentiated by one tooth from that of the first gear and idly fitted to said shaft, a dial plate rotatably supported by the second gear and an idle gear engaging the first and second gears;

a feed screw rotated by said shaft; and.

a guide member fitted to the second guide block so as to be moved along the central axis of the screw by rotation of said feed screw.

3. The variable metering pump according to claim 1 wherein the lubricant system comprises:

a centrifugal pump for delivering lubricant coupled with a driving shaft rotated by the power source; and

an oil filter unit for eliminating foreign matter from the lubricant delivered from the centrifugal pump, thus supplying purified lubricant to the sliding portions of the reciprocating mechanism through the oil filter unit.

4. A variable metering pump comprising:

a pump unit including a plunger;

a first guide block rotated by a power source;

a second guide block facing the first guide block;

a first groove formed in that surface of the first guide block which faces the second guide block;

a second groove formed in that surface of the second guide block which faces the first guide block;

a ring disposed between the first and second guide blocks and having a first key mounted on one fiat end surface thereof and another key formed perpendicular to said first key on another flat end surface thereof, said keys being fitted into said first and second grooves respectively;

a reciprocating mechanism including a connecting rod, into one end of which there is fitted the ring and theother end of which is connected to the plunger of the pump unit;

means for causing the second guide block to slide over said one flat end surface of the ring thereby to adjust the strokes of the plunger of the pump unit; and

a lubricating system for lubricating the sliding portions of the reciprocating mechanism.

5. The variable metering pump according to claim 1 wherein the surface of the first guide block in which said first groove is formed and the surface of the second guide block in which said second groove is formed are fiat.

6. The variable metering pump according to claim 1 wherein the first and second flat surfaces of the ring are opposite each other.

7. The variable metering pump according to claim 1 wherein said one set of rollers fitted into said first groove are on the first flat surface of said ring, and the other set of said rollers fitted into said second groove are on the second flat surface of said ring. 

1. A variable metering pump comprising: a pump unit including a plunger; a first guide block rotated by a power source; a second guide block facing the first guide block; a first groove formed in that surface of the first guide block which faces the second guide block; a second groove formed in that surface of the second guide block which faces the first guide block; a ring disposed between the first and second guide blocks and having rollers mounted on first and second flat surfaces thereof in perpendicularly intersecting rows with one set of said rollers fitted into said first groove and the other set fitted into said second groove; a reciprocating mechanism including a connecting rod, into one end of which there is fitted the ring and the other end of which is connected to the plunger of the pump unit; means for causing the second guide block to slide over the second flat surface of the ring thereby to adjust the strokes of the plunger of the pump unit; and a lubricating system for lubricating the sliding portions of the reciprocating mechanism.
 2. The variable metering pump according to claim 1 wherein the plunger stroke adjusting means comprises: a reading device including a first gear fixed to a shaft for driving the plunger stroke adjusting means, a second gear having a number of teeth differentiated by one tooth from that of the first gear and idly fitted to said shaft, a dial plate rotatably supported by the second gear and an idle gear engaging the first and second gears; a feed screw rotated by said shaft; and a guide member fitted to the second guide block so as to be moved along the central axis of the screw by rotation of said feed screw.
 3. The variable metering pump according to claim 1 wherein the lubricant system comprises: a centrifugal pump for delivering lubricant coupled with a driving shaft rotated by the power source; and an oil filter unit for eliminating foreign matter from the lubricant delivered from the centrifugal pump, thus supplying purified lubricant to the sliding portions of the reciprocating mechanism through the oil filter unit.
 4. A variable metering pump comprising: a pump unit including a plunger; a first guide block rotated by a power source; a second guide block facing the first guide block; a first groove formed in that surface of the first guide block which faces the second guide block; a second groove formed in that surface of the second guide block which faces the first guide block; a ring disposed between the first and second guide blocks and having a first key mounted on one flat end surface thereof and another key formed perpendicular to said first key on another flat end surface thereof, said keys being fitted into said first and second grooves respectively; a reciprocating mechanism including a connecting rod, into one end of which there is fitted the ring and the otHer end of which is connected to the plunger of the pump unit; means for causing the second guide block to slide over said one flat end surface of the ring thereby to adjust the strokes of the plunger of the pump unit; and a lubricating system for lubricating the sliding portions of the reciprocating mechanism.
 5. The variable metering pump according to claim 1 wherein the surface of the first guide block in which said first groove is formed and the surface of the second guide block in which said second groove is formed are flat.
 6. The variable metering pump according to claim 1 wherein the first and second flat surfaces of the ring are opposite each other.
 7. The variable metering pump according to claim 1 wherein said one set of rollers fitted into said first groove are on the first flat surface of said ring, and the other set of said rollers fitted into said second groove are on the second flat surface of said ring.
 8. The variable metering pump according to claim 4 wherein said one flat end surface of said ring faces the first guide block, and said another flat end surface of said ring faces the second guide block. 